1 files changed, 6 insertions, 6 deletions
diff --git a/test/Test.hs b/test/Test.hs
index 3b15d25..bfe9f55 100644
--- a/test/Test.hs
+++ b/test/Test.hs
@@ -21,12 +21,7 @@ import Chess.PGN
 import ArbitraryMove
 
 atAnyState :: (Board -> Bool) -> PGN -> Bool
-atAnyState ok pgn = and [ok b | Right b <- seqList [moveSAN m | m <- moves pgn] $ Right defaultBoard]
-  where
-    seqList :: [r -> Either e r] -> Either e r -> [Either e r]
-    seqList (f:fs) (Right io) = f io:seqList fs (f io)
-    seqList _      (Left _)   = []
-    seqList []     _          = []
+atAnyState = atAnyTwoStates . const
 
 atAnyTwoStates :: (Board -> Board -> Bool) -> PGN -> Bool
 atAnyTwoStates ok pgn =
@@ -107,5 +102,10 @@ prop_number_of_pieces = atAnyTwoStates (\b1 b2 ->
   length (pieceCoords Nothing Nothing b1) - 1 == length (pieceCoords Nothing Nothing b2)
   )
 
+prop_not_in_check_twice :: PGN -> Bool
+prop_not_in_check_twice = atAnyTwoStates (\b1 b2 ->
+  not (check Black b1 && check Black b2) &&
+  not (check White b1 && check White b2))
+
 return []
 main = $forAllProperties (quickCheckWithResult (stdArgs {maxSuccess=10000}))